SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '50da6ab42d34a9f25768520cb31f0e2385a8c4743116ce90689ab73d356f7994' 
  AND token = 'ySj2k+fgGvAXGYd0SCtdT6tXtGnUoB/w6D499lUaaC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}